docs: def numRegisteredForRole(self, role, includeTemporaryRegs=False):
          '''
          Accepts a DanceRole object and returns the number of registrations of that role.
          '''
          count = self.eventregistration_set.filter(cancelled=False,dropIn=False,role=role).count()
          if includeTemporaryRegs:
              count += self.temporaryeventregistration_set.filter(dropIn=False,role=role).exclude(
                  registration__expirationDate__lte=timezone.now()).count()
          return count